6678812781 has 12 divisors (see below), whose sum is σ = 9979835580. Its totient is φ = 4299005760.

The previous prime is 6678812773. The next prime is 6678812783. The reversal of 6678812781 is 1872188766.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4162185225 + 2516627556 = 64515^2 + 50166^2 .

It is not a de Polignac number, because 6678812781 - 2³ = 6678812773 is a prime.

It is a super-2 number, since 2×6678812781² = 89213080327297907922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6678812783) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12794400 + ... + 12794921.

It is an arithmetic number, because the mean of its divisors is an integer number (831652965).

Almost surely, 2^6678812781 is an apocalyptic number.

It is an amenable number.

6678812781 is a deficient number, since it is larger than the sum of its proper divisors (3301022799).

6678812781 is a wasteful number, since it uses less digits than its factorization.

6678812781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25589356 (or 25589353 counting only the distinct ones).

The product of its digits is 1806336, while the sum is 54.

The square root of 6678812781 is about 81724.0037014830. The cubic root of 6678812781 is about 1883.2143574374.

The spelling of 6678812781 in words is "six billion, six hundred seventy-eight million, eight hundred twelve thousand, seven hundred eighty-one".